Telephone system.



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F. W. DUNBAR.

n TELEPHONE SYSTEM.

APPLlcMIoN man umso. 19m.

l* Patented Apr. 17,1917.

q2 Inventor.

17711;@ W `Dunbar/r' B LA y tty.

Witnesses:

F: w. nuNAR,` TELEPHONE SYSTEM ArPLlcATloN HLEIJ necfao. i904. PatentedApr. 17, 1917.

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TELEPHONE SYSTEM. APPLICATION FILED DEC.30 1904 Witnlesses: a. (QJ/ n,um MM A.

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F. W. DUNBAR; TELEPHONE SYSTEM. APPLlcAlon man nzc.30. 1904 r Fm .wwm., 1. N W D .w.

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UNITED s'rArEs :PTENT FEANCIS'W. DUNBAE, OE CHICAGO, ILLINOIS,As'sICNOE, BY MES NE AssIGNMEN's,-fro

`KELLOoe SWITCHEOAED a; SUPPLY COMPANY, A CORPORATION OE aILLINOIS.

`TELEPHONE SYSTEM.

Specification Of Letters Patent.

To all whom it may concern.'

Be it known that I, FmNc-Is lV. DUNBAR, a citizen of the United tates,`residing at Chicago, in the county of Cook and State ot Illinois, have`invented a certain new and useful Imlin'ovenient in Telephone Systems,of which 'the following is a full, clear., concise, and exactdescription, reference being had to the accompanying drawings, torming apart of this specification.

My invention. relates to telephone cxchange systems, and has for itsobject the simplification of operators line equipment present upon theoperator-boards,` and also has for its object the provision of improveddistribution of the ilistrumentalities employed for uniting'sul'iscribers for converst tion whereby theetiiciency ot the equipmentmay be greatly increased. My invention is practised by providinganswering-jacks (either in the sense such term is used in multipleswitch-board practice or in the sense of any jack used with which cordcircuit connection is made to answer a calling` subscribcr) for aplurality of telephone lines and selective switching mechanisn'i incircuit relation with the lines whereby these jacks may become connectedwith calling tele phone lines, whereafter suitable cord con* nectingapparatus, such, for example, as 'conmuiuly employs two plugs to eachcord outfit, may be used tor uniting a calling'` line with a calledsubscribers line, the answering; plug` of an operators cord circuitbeing for the purpose engaged with the jack selectively connected with acalling line, the `linejaclt, preferably permanently connected, ot' thccalled line receiving;r the connecting plug.` Reference is here madetomy copending almlication, Serial No. 237,445, tiled ])eccmber 1i),1904. The present application differs from said (xo-pendingr applicationby connectingv the selective switches with the answering"jacks. Thereare con'lparatively yfew answering-jacks as compared with the group oftelephone lines with which they are associated and there may he as manycord circuits as there are answeringjacks or` the cord circuits may beson'icwhat in execs.; ot' the number of 'answering-jacks provided to`allow tor inunl'rlnel'it ot' such cords. The jacks are-desirably in theforni oi. sleeves or thimblcs, behind which are vthe cord circuits withcalling lines.

fore, use the term answering-jaclts 'and disposed springs tha;Uconstitute the jacks spring jacks and tle elements of the cord circuitsthat are des gned for engagement with these jacks are `formed intocorrespond-4 ing plug ever, to the shape oi the jacks nor to the shapeot' the answel ing` .ends of the cord circuits that are maiually appliedtheretol' For example the ans wering-jacks might in the form of plugsn'iounted upon thefoplerators board and the; answering-,plugs might beinthe form of sleeved elements to` ride over the yansweringljacks, inthe form ot plugs, to etiect thi deslredfconneotion of I,thereanswering-plugs in the broad 'snse here indicated, as I do no iwish to be 'limited to the meclianical constfuction of the answer`ing-Jacks. nor to the mechanical construction of the answeringf-ternnnals of the cord circuits manually manipulated by the operi ln`multiple switcl' -board prac-tice 'eyerv. `ciitort has been made toprovide room upon, the multiple boards for as many jacks as possible, Tothis enl the jacks have been placed on three-tent is inch centersverti-A cally and lmrizontally, while the lamps in association with theanswering-jacks have -v been placed on centers three-tenths of an inchapart horlzontzlly and one-halfen inch apart vertically. In the presentSwitchf,

board practice there are from three hundred to tive hundritanswering-jacks and as many line-signals to each' three position sectionof a multiple Y ioard, which obviously take` up a great deal if roomthat would be very desirable for lir c-jacks.

1t isoae of the ol'uectsot my invention,

as hitherto stated, torcducc the operators line equipmcut'and lVaurenabled by means ot :my uwention to du pense `with most ofthe j,answering' jacks and line signals? asjby,l ,in eans ot my inventio 1thirty jacks, whether of the sleeved or' p ug construction, may

Pate Lited pr, 17,1917.

I do not v .ish to be limited, how- L Y serve yforeach-section of theswitchboard and face of the board.

Another object of my inventiony is to simplify mechanical inter-relatlonof the cord circuits and the answering-j acks, which object isaccomplished by having the selectwith multiple the lines ing mechanismassociated with from left select the jacks in their order, say

to right rather thanpromiscuously, so that the answering-ends of thecords will lead to the answering-jacks in an orderly fashion one afterthe other, instead of being indiscriminately distributed intoassociation with the answering-jacks of the switchboards according topresent practice, for switch-boards now in use the 'mdiscriminatedistribution of the answering-ends of the cords is accompanied by aninter-weaving of these cord ends, so that it is diiiicult in effectingdisconnection to pick out the connecting ends that mate with theanswering ends, which confusion isgreatly lessened, if not altogetherdispensed with, by means of my invention.

In accordance with another feature of my invention the lines, theanswering-jacks and the selective switching mechanism controlling theassociation of the answering-jacks with the lines, are so inter-relatedvthat the operators at one section -of the board are n fully supplied totheir capacity before the operators at an ensuing section are employed,the operators at said ensuing section being fully supplied with workbefore the indicators and -jacks are 'I erent sections of the loperatorsat the next section are employed, and so on throughout the system,whereby the "most economical method of operating the exchange isprovided. i

In multiple switch-board practice it is well understood by those skilledin; the art that each line has in addition to the multiple jacksdistributed throughout the boards of the system, an answering-jack and aline-indicator, the answering-jack and indicator of each line beingcollocatcd. These distributed in quantity among the difswitch-board, soVthat there is disposed at all operators positions thesame number ofanswering-jacks andthe same number of line-siglials. It is, of course,apparent thattelephone operators possess varying degrees of skill andspeed in handling calls. The uniform distribution of answering-jacks andline-indicators renders it difficult and impracticable, in accordancewith present practice, to apportion work to suit the capacity of thedifferent operators. can properly. attend to two hundred seventy oups ofuniform business at board, so as The ordlnary skilled operatory calls inan hour, if the calls be uniformly distributed throughout the sixty-minutes The average time or length of each call is, approximately, oneminute twenty seconds, thus allowing each cord circuit to completeforty-five calls per hour, if kept busy throughout the sixty minutes.Six cord circuits kept uniformly busy throughout the hour can,therefore, handle two hundred seventy calls during the hour-the work ofthe ordinary operator. Certain operators can, however,W handle in aproper manner more than two hundred seventy calls per hour, whileothers, less skilled, are unable to handle properly as many seventy. Ipreferably provide means whereby one or more answering-jacks at eachoperators position may be thrown out of operation or out of operativerelation with respect to the lines, whereby each operator .may be givenas many answering-jacks in operative relation to the line-circuits ascan properly be attended to by'her. Thus, certain operators may have butthree or four answering-jacks in operative condition while others,highly skilled, may have eight, nine or even ten answering-jacks placedin operative relation to the lines. By this means each operator may bekept as busy as her degree of skill will permit and paid according toher ability or skill, the number of answering-jacks which she can attendto efficiently being a correct gage or measure of the number of callswhich she can handle efiiciently per hour.

It may be properly assumed that oneeighth of the total number of callsmade during the entire twenty-four hours ofthe day will occur during thebusiest hour. The switch-board must be designed to handle the all hoursof the day. Consequently board is determined. by the number ofvoperatorsrequired to handle the business during the busiest hour. If duringr thisbusiest hour or moment, each operator be emanswering jacks and callingsignals throughout the various sections of switchto cause as uniform adistribution as possible of the calls during this busiest hour ormoment. At best, however, owing to the daily iiuctuations in the amountof business from certain groups and from all classes of lines, it isimpossible to distribute the said jacks and calling signals so as tosecure more thana rough approximation to a uniform distribution ofcalls.

By means of my invention, however, a

as two hundredthe number of sections of switch-v i 50% or moredistribution of calls may be automatically secured, such that whenthenumber of answering-jacks inoperative relation with the calling linesis properly proportioned among and accordingr toy the'slill of theindividual operators, each operator vvill be Working at her maximumefficiency not only during the busy hour but at all hours. Consequentlythe necessary number of sectionsof switch,- board will .be decreased.and fewer operators at all hours of the day will be required.

In all present systems of telephony the calls at all hours of the dayare distribuir-edil throughout the entire switch-board, `this re quiringthe presence ofone or more opentors at each sectionof the board at alltimes, save certain of the night hours, when the business i.' so slackthat from one yto ten operators-depending upon the size oftheexchange-can handle the entire number of calls `by walking fromsection to section and liiicking up vthevarious calls they may come in.At all such times the efiiciency of the operatorsreckoned on a .basis ofnum ber of calls answered per hour-is very low, the result being thatthe average number of calls handled per operator per houx-through` outthe twenty-four is less than half the numbl` Which the average operatoris able to handle efficiently were she kept uniformly busy. tf',

By means of my invention l amenabled to distribute the calls so `thatduring the night hoursall the calls will. appear at the first section ofthe sWitch-board-oi.' at the first two or three-dspending` upon the sizeof the exchange and. the volume of night business, so. that, as thebusiness increases, operator" after operator ina,y be added asrcquired--thc first or lowerfnumbered sections being always busy and thehigher numbered sections coming' graiilually into pperation as the busyl'iours approach. I aml .thus abled.. to secure the same average numberof calls answered per operator per hour throughout` the twenty-four asis secured.

during the busiest hour of the day-resulting in a decrease in operatingexpense of l. do` not contemigiilate, however, in large exchangesproviding the neces-` sary switcliinp; facilities, so that each line ymay be connected with any one ot all the answering-jacks, altl'lough insmaller switch boards it would he pre'lerable` to do large exiithangcs Iprefer to divide the lines into groluis of several hundred each anddivid e the a uswering-j a che into a min'lfesl'ionding number ofgroups, so that any line in a acrtain. group .l'nay` be connected 'withany answe )Hek assigneiil to that griimp, if `the lower. numberedanswering-jack of that group'alrea( f be busy. lf that particular one benot hi y, the first :idle answering-jack thus selected, willautomatically make connection with a calling subscriber.

For example I will assume an exchange of'four thousan d five hundredlines and pro- `videfa group oE thirty answering-jacks for .eachfivehund red lines, thus .making two `hundred seventy answering-jacksin all,di- ,vided. equally between nine sections of switch-board, fr thirtyanswering-jacks to the section (inszead of'threehundredrto five hundredas hitherto) and ten tothe opera- "than ythree calling linessimultaneously con nected in conv irsation-in which case the fourth lineof thatygroup making a "call While the other three call-ing parties of:the same group We c still connected, would i'ndicate at the fir 4tposition of the second section. A fifth c lll from the same groupoccurring while t 1e other four `Were still convel-sing, would z ppearat the second position of the second section and would necessitate theoperator lea vingher position at the first section to atterd toit. Sucha condition 90 would not be apt, however, to arise, as itWoul.cl"i'equi1e (assuming one operator only was needed for the businessat this time) five`-sixths of tl e total business which this singleoperator could efficiently handle, to originate in a group containingonly oneninth. of the tot: `l number of lines.

.'[nthe `example chosen as an illustration, I would. employ thirtyselector switches for each group of ive hundred lines, each `se 100lector switch including five hundred sets of line terminal contacts.

In the embodiment of my invention herein specifically set forth, theanswering-jacks are each provi( ed with a pair of moving 10.5 terminals(the switch-bimrd illustrated being a metallic s vitchboard, theapplication of the .iilyention to grounded. lines being. wellundcrsti'iod by tlose skilled in the art) and motor mechanisn jointlycontrolled b y the 110 answering-jack :ujn'iaratus anda callingsubscribers apparaus for effectingengagement Abetween theseterminals,-ivhich l shall call answering-jack terminals and the.terminals of a callin.; line. nism has such-an assoc. 'ation with theansweringjack circuit. and apparatusthat only `the idle answer ugr-jacksareautomatically .prise traveling sivitchearms adapted to pass overterminals cf telephone lines and may, 130

This motor mecha- 115y eration by a calling 1ngjacks. Themotorcontrolled switching mechanism, which may easily be set `intoopsubscriber, 1s so lnterv related with the answering-jack circuits andelectro-magnetic mechanism governing the operation of the motormechanism actuating the answering-jack terminals, that only suchanswering-jack terminals that are associated with idle answering-jacksare operated by the motor mechanism in mechanical relation therewith. Inother words, in the embodiment of the invention herein specifically setforth the calling subscriber causes the motor mechanism associated withthe answering-jack terminals of an idle answering-jack to bring saidterminals into connection with the terminals of a calling line. Uponsuch connection of the traveling terminals of an idle answering-jackwith a calling line, the lnotor belonging to the answering-jack iscaused to stop, preferably by means of electro-magnetic mechanism whosecircuit conditions are changed upon this establishmentof connectionbetween an idle answering-jack'and a calling line, such electro-magneticmechanism thereupon effecting the stoppage ,of the motor, which resultis accomplished where the motor is an electric motor, preferably byaltering the circuit of said motor. The lmotor controlled switchingmechanism governed by a calling subscriber, is preferably common to eachgroup of lines, there being as many such switching meclianismsas thereare groups. I'do not wish, however, to be limited to such anarrangement. Where such motor controlled switching mechanism is madekcommon toa group of lines, conductors from all the answering-jackcircuits belonging to a particular group are placed in tiontherewith andsaid switching mechanism is caused to travel over terminals of theseconductors. The 'electrical condition of' these terminals kdepends uponthe condition of' use ofthe answering-jacks. If the answering-jacks areidle, the electrical character of the terminals is such that when themotor controlled switching device comes into contact with the first ofsuch terminals assoeiatcd with an idle answering-jack, the

.electrodnagnetic mechanism is operated to whereby said answering-jackterminals cor- I responding to the answering-jack motor are electricalassociai caused to .engage the terminals of a calling line, whereuponsaid answering-jack motor is thrown out of action. lVhen the terminalsengaged by the motor controlled switching Adevice have their associatedansweringjacks busy, the electro-magnetic mechanism immediatelygoverning the operation of the answering-ack motor has no operativeeffect upon said motor, which thereby remains quiescent. I shall termthe motor controlled switching device governed by calling subscribersthe subscribers governor motor and the motor which directly operates theanswering-jack terminals the. answeringjack motor, as such terms havepreviously been used.. In order that special line signals will bedispensed with, a signaling device, preferabl7 a signaling lamp, `isassociated ywith each answering-jack and suitable governing apparatuswhereby it may manifest a signal to the operator when a. callingsubscriber initiates a call. A call having been initiated, the operatormanually associates the answering endof a cord circuit with theanswering-jack of a calling line and manually associates the connectingend of the same cord circuit with a line-jack of the calledsubscribers'line. This provision of a line-jack to each line to theterminals of each line that are multipled together and are associatedwith the traveling answering-jack terminals, is an important feature ofmy invention, inasmuch as by its provision the connecting end of eachcord circuit` may in conjunction with its connecting plug, be under themanual control of the operator; The traveling answcring-j ack terminalsmove over their companion sets of line -terlninal contacts (which lattercontacts are, as stated, multipled together) when their correspondingmotors are set into operation. Thus, in the example specifically chosen,each line has thirty sets of line lterminal contacts in coperative'relation with the traveling terminals of thirty answering-jacks and eachanswering-jack has its traveling terminals in coperative relation withfive hundred sets of telephone line terminal contacts.

I shall term the conductors th at extend bein addition tween thedifferent groups of lines A and the answering-jack at the secondoperatorvs po' sition of the first board, the third answeringjackcircuit having its answering end connected with the answering-jack atthe third operators position of the first board, the

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fourth answering-jack circuit having its answering end connected withthe answering-jack at the lirst operators position of the second sectionof the hoard, the fifth answering-jack circuit having its answeringsection,` the sixth` answeringjack circuit havingits answering-endconnected with the answering-jack at the 'third operators posi# rtion ofthe' econd section, and so on.

I have indicated ten answering-jacks at each 0];)erators position, and,in order that no operator may receive calls to such an ex tent. that shecannot attend to them, provision is made whereby answering-jack circuitsmay be made to correspond with busy answering-jack circuitsartificially, in order that when a less -eilieient operator has reachedher capacity, her answering-jack circuits which havebeen incapacitatedwill not be connected witha calling line, but, on the other hand,connection will` be effected between saidy calling line and an idle ani11gjacl: circuit at another operator-s position. It will be seen thatif each of the thirtv'answerinU-'aclt circuits is worked to.

its maximum efficiency, said circuits will be capable of taking care oftorty-five callsl per hour,y or a total oi one tl'iousaml thi'ee hum dred fifty calls during: the busy hour, represei'iting an average ofcalls` per subscriber during the busy hour, or 21.6 per subscriber perday. Ample margin is thus present for a retfluction in the total numberol. Vansweringjaek circuits in service to an average of seven or eight'per operator, whereby facilities are furnished for handling a greaternumber of calls per day than will originate in an average exchange ofthe chosen 1 invention to-.sucl'ipractice.

I will explain my invention more fully by .reference .to th.accompanying drawings illustrating vthe. thereof, in which-n l"igures 1,2, 3 and 4 illustrate smnewhat fullytelephone exchange systems equippedwith 'the al'iparatus of my invention.

Fig. 5 is agi-,neral diagrammatic view illustratil'lg one distributionof the answering-jack circuit: which may be varied to preferredeinhmlinlents i suit different exchanges. l

iigures.

Fig. G is a view :llustrating another coni struction of line-jack andanswering-plug.

Like parts are in( icated by Similar characters of reference t 1roughoutthe Adiiferent Each subscriber-s station A-fB :is provided withcustomary common battery subscribens apparatus, a switch-hook at eachstation servingl operatively metallically to unite the sides oi the linewhen the receiver is removed. I do not deemV a detailed description ofthe subicribers station apparatus to be essential, as the illustrationis sufficient to make the` s: une understood by those skilled'in theart. Although I have illustrated one arral'lgenient of subscribersstation apparatus,`it will be obvioustothose skilled in the art tratother4 arrangements may be employed -at :he substationgand 'I do notwish to be limited tothe arrangement and l. apparatus shown, mo do Iwish to be hunted in all embodiments of the invention. to itsapplication to a ctmmon battery system. The subscribers lines indicatedare metallic lines and each extends vin two branches to the exchange,where ;hey terminate in armaturee l-1 of a cutiti' relayQ. The,alternate contacts' of th e armatures constitute terminals of the officeend Vof the line which lsupplied with the line-jacks 3 that I havespoken of. The :em illustrated` being a multiple switcl1-boarl system,there are also provided upon othel sectionsefthe hoard than where jack 3is located, other jacks 4 in connection with ,he said alternate contactsand the oiiice rnd ot the line similar to the connection of jackMultipled terminals 5*:5 and nu ltipled terminals (S-G are provided foreach line which are connected with the alternate contacts of thecut-ofiA relay switches and form what I have herein spoken of as thetelephone line terminal contacts when the armatures 1`.--1 of said relayare attracted. The contact buttonel or terminals 5--6 are desirablyarranged in circular rnvs over which sweep the answering-jack terminals7-8 and VM-S', which answering-jack terminals are desirabl y not normally col'mected. with the answering-jack, but `vhich` as indicated inconnection with the terminalsj78, are caused to form contil' nations ofthe answering-jacl' circuit upon the operation of an arnnlture-switchinch ding a tipv switch con-A tact f) and. a sleeve switch contact l()gov erucd in, `their movement by a relay 11 under oircumstalu'es to i beherelnattcr set forth.

vThere is also an additional circular row of contact buttons 1 2 overwhich sweep contact arms 1l13 that take part in controlling the` motionli'vthe terminals` 7-8 and 7-8'. The nun ber of contact buttons 5 andalso 5', the nun berof contact buttons and also and the nlu'nberofcontact buttons l2andxa1so 12', each equalsthe num.-

ber of telephone lines to which a group of answering-Jack circuits hasYbeen assigned. For example, if thirty. answering-jack circuits have beenassigned to a group of five hundred linesJ the contact buttons 5 numberYing a shaft 14 forming a part of the common prune mover upon which itmay be understood the arms 7, 8 and 13 arer mounted. There are thus asmany prime movers as there are answering-jack circuits. The

' prime mover 15 illustrated upon the left of each of the drawings iscomposed of a spring motor 16 in driving engagement with the shaft 14and a wheelv 17 upon said shaft, -which wheel isprovided with a`plurality of off-set teeth 18-19 arranged in peripheral rows, acrosswhich teeth the polarized armagture 20 of the motor is adapted tooscillate by the agency of the field windings 21 and lthe sourceofalternating current 22 when said source of current is included in aclosed circuit with said windings. The said armature in operating isremoved from engagement with one tooth 18 into the path vof an ofi-settooth 19, whereupon the spring motor may move the wheel a step,whereafter the armature is oscillated to its initial position into thepath of a new tooth 18 that is olfsetv'with respect to the previouslyengaged tooth 19, whereupon the spring motor may move the wheel 17another step, and so on, until theQ source of current 22 `has thecircuit including the same opened.

In the motive device shown upon the right of Figs. 1 and 2, a source ofdirect current, as the common battery 23, may be employed to operatethe'ield winding 2,4, lwhich isV alternately energized and denergized,so that the armature 25 may be attracted from engagement with the teethin the row 26 and brought into the path of the teeth in the row 27offset with res )ect to the teeth 26. Upon this attraction o thearmature, the circuit through the magnet 24 is opened, whereupon thespring 28 restores the armature to its initial. position. In this way aspring motor, which is assumed to be in driving engagement with theWheel bearingl the teeth 26-27, may cause the answering-terminals of theanswering-jack circuit to move from one line-contact to the next, uponthe denergiza'tion of the magnet 24, and as the result of the retractionof the spring 28.

I will explain the circuit arrangements ofYV the magnets 21-22 and theapparatus by which such arrangements are controlled more fullyhereinafter. 4

, When a subscriber initiates a call, the answering end of an idleanswering-jack circuit, in this case the first, is automaticallyconnected with a set4 of terminal contacts, as the contacts 5 6, forexample, this automatic connection being occasioned by the operation ofthe said answering-jackcircuits motor. Only one answering-)ack circuitmotor, that correspondin to an idle answering-jack circuit, is preerably operated in automatically effecting the movement of theanswering-terminals' of said answering-jack into contact with theterminals of a calling line. To' this end I preferably employ selectivemechanism, consti-IV tilting an electric motor, that serves to selectthe answering-jack circuit motor that is to be operated, which selectingmotor may be termed the f calling subscribers governor motor and thereis preferably only one such motor common to a group of telephone lines.Referring again more'particularly to the systemillustrated in Fig. 1,this governor motor includes in one embodiment of the invention atraveling switch 29 operated by the armature of an electro-magnet 30, aswill hereinafter vbe particularly set forth, which switch 29 rides overaseries of contact buttons 31, constituting terminals of conductorsextending to the various answering-jack circuits of a group, there beingas many contacts 31 as there are answering- 100 jacks of a particularlot assigned to a group of lines; there are in the example chosen thirtysuch contact buttons 31. A complete conductor 32 is shown extending-fromone of the contact buttons 31 to the answering- 105 jack circuit that isshown uniting the subscribers stations A and B." Normally, that is,when-its answering-jack circuit is idle, this conductor32 is connectedwith the grounded battery 23 by way of the switch 110 33 governed by therelay 11. The switch-29 is normally disconnected from ground, but,

vas will hereinafter be more fully set forth,

ture-switch 35, constituting a terminal of 12o.

the generator 22, is attracted to complete the circuit through'themagnet v21 and said generator, the switch 36 controlled by magnet 11,then being upon its grounded contact.

When, therefore, the switch 29 is moved vby a 125 calling subscriberinto connection with a conductor that is 'completedat 33, theanswering-jack circuit motor of the answering-jack circuit'correspondingto saidV conductor is set into operation. y But where theswitch 29 encounters the terminal of a con ductor 32 that is open at 33,as is always the case where the corresponding answering- ]ack clrcuithas been lautomatically con- I nected with a calling dine, said switchis caused to pass said opened conductor and to continue its operationuntil it encounters ay conductor that is closed at 33 that is, a` placesimilar to 33. lVhen the switch 29 encounters the terminal of aconductor V,32 that is sociated` with the calling telephone line,y

the magnet 11. becomes energized in a manner more fully hereinafter tobe set 'forth, to operate the armature switches- 910, to complete theconnection of the answermg-Juclcwith the said line-terminals, to openthe conductor at 33, to open the circuit of the answering-jack circuitprime' mover at 36, and to close a subsidiary path through the windingof` magnet 11 to main tain it energized irrespective ot' subsequentchanges occurring in the apparatus associated with the calling line, thearmatllre switch 37 engaging its contact, which is a pivoted one. beforesaid contact breaks connection with the contact it in turn noclnallyengages. As one of the results of these cir-` cuit changes, theanswering-jack circuit motor ceases 1ts operation, so that the answeringend of the. selected answering-jack cir- `against'.their groundedcontacts, 39 being preferablygrounded before 40. The switch 3f)connected with a conductor 4l that is common to all of the lines andwhich eX- tends to the switch 29 and which is the conductor that isgrounded in order to cornplete the circuit containing the conductor 32,when said latter conductor is closed at 33 as heretofore set forth,whereby results that have hitherto been specified are accon'iilished.This salnc conductor 4l has a branch 42 that is connected with thegrounded battery` 23, which conductor 42 includes the winding of themotor 30, the switch-arm 43 governed` inits operation by the arma` tureof said motor 30 and thearmature 44 an extension of switch f:

.switch to its normal or initi position.

vwith its Contact, said latter armature belonging .to the relay 45. 'Tlus, the switch 29 '1s not only grounded at 39` but the magnet 30 isincluded in a ground ed h'cireuit, whicl1 circuit is intermittently opcned `by the separation of the lazy arm 43 from its contact,1 due to theoperation of the armature of the magnet 30 and the coperasion of anexten-y sion of said armature beiweenthe bifur-l cated ends of said armiThe arm 43 is forced away from its cont actfupon the attraction of thearmature ly the magnet 30 and is restored to engagement with its contactby the springin con! ection4 with Said armature, the said armata 'ebeing thus intern'iittently attracted as l( ng as the circuit icontaining the magnet 30 is otherwise closed. Said armature cooperates"vith the teeth of whereby the said switch is caused to tr: `vel as thearmature is intermittently attr acted. The dog 46 engages the said teetht) prevent the restoring spring47 from operating until required, so thatthe switch 129 is maintained in any position, for the tim c being, inwhich it has been placed by the inotor 30. When the switch 29 encountersa conductor 32 that is closed at 33, circuit whrough the magnet 45 isobviously closed the winding of this magnet being includel in the'conductor 41, whereupon the ar. nature 44 is at tracted to bring the`catch 48 into-.connection with the catch upon the dog or detent 4Gpreparatory (but not at this time in connection with the system siown inFig.v l) to releasing the said detert from mechanical locking engagementwith the switch 29 to permit the spring 47 tc restore the said The cmagnet 45 remains energized until the circuit containing the conduc.101*32 is open at 33, which only is accomr lished when theanswering-jack circuit mot r selected by the subscribers governor moto:i has brought the answering-contacts ot' its a ;soc`iated answering-jackcircuit into conne( tion with calling line terminal contacts. T 1econnection of the answering-jack circuit with the calling telephone linehaving thus been effected, circuit through the magne.` 45 is opened at33, whereupon the spring lll lifts the dog or det-ent 4G, permitting thes )ring 47 ,to withdraw or restore the switcl 29 to its initialposition. In order that tl e switch 29 may not through some fault in theoperation of the apparatus, or in case al 'answering-jacks arebusy, passall of the co itacts 31 without causing the selection of a 1answering-jack circuiti and thereafter be not restored, I1" provide asupplemental cintact buttonl50` which is engagedby the brush 29V onreach ing the limit of its excursion, whereupon circuit is completedthat m: ty be traced from y the ground at 39 occasioned by `the callingsubscriber, the magnet 45, he switch 29g/,the

"minal switch 8, the ground at the cut-off ref lnormally grounded at 56.

contact button 50 and the grounded batter 23, whereupon Athe armature 44is attracte with the results hitherto specified, the circuit through themagnet 45 is opened at 51 and the springxfl) is permitted to withdrawthe detent 46, whereupon the spring 47 restores the switch 29. In orderthat some of the answering-jack circuits may be rendered inoperative, sothat work assigned to less eflicient operators may be reduced, theconductors 32 may each include a switch 52 that may produce a break insaid conductor similar to that produced at 33 when the magnet 11 isenergized, so that the switch 29 will not pause at a contact terminal ofsaid conductor, but will pass the same as if the answering-jack circuitassociated therewith were busy. In order that my invention may ,beeffectively practised, the magnet 11 (which is the one that determinesthe connection of the selected answering-jackvcircuit with the callingt'elephonelline, determines the continuity of the circuit including thegovernor motor, and controls the electrical character of the butt-ons 31by controlling the conductors 32 and 33) is referab'ly included in acircuit that is istinct from the talking circuit, which circuit includesa conductor 53 that terminates in the armature-switch 40, there beingone such armature-switch 40 and one such conductor 53 for each telephoneline. This conductor 53 is connected with the contact but;- tons 12-12,etc., associated with the answering-jack circuits, there being, ashitherto stated,`as many such contacts 12 and as many such-contacts 12,as there are telephone lines in a 'particular group. The switch-arm 13,for example, coperates with the contact buttons 12, the said switch-armmoving with the switch-arms 7-8 until it encounters the conductor 53that is grounded at 40 by the calling subscriber, whereupon circuit isclosed from said ground at 40 through the grounded battery 23 by way ofthe switch-arm 13, the button 12 engaging the same and the pivotedswitch-contact 54 engaging its normal ycontact The magnet 1l is thusenergized to bring the switcharms 9-10 into connection with the contactsof the calling-subscribers line, while the armature-switches 33, 36 and37 are moved by said magnet when thus energized, whereby the said magnetis .included in a circuit containing the battery 23, the contact 54, theswitch 37, and the conductor 56 Circuit is also established from thegrounded battery 23 through the answering-jack circuit relay 57, thesleeve side of the answering-jack circuit, the armature-switch 10, theanswering terlay 2 and also the ground at the relay 58 `that isconnected with the tip side of the answering-jack circuit and whichground is met 593.

vthe agency of the plug that brings reached over the subscribers line byway of the answering-terminal 7 and the armatureswitch 9. The operationof relay 57 permits relayll to continuously hold its armaturesattracted, since when the armature of relay 57 is attracted, it engagesits alternate contact, and when breaking connection 56, 56', completes amaintaining circuit for relay 11, through contact 5 592, attractedarmature ofrelay 58, signal 59,relay 89', to ground, the armature ofrelay 58 bein attracted in time to prevent retraction of t ose of relay11. The magnet 11 will thus be unresponsive to any change in theposition of the switch 40 and the cut-oii' relay 2 will be energized,whereupon the armatures 1-l will be attracted and the switches 39-40restored to their normal positions, whereby the connection between anidle answering- I jack circuit and a calling line is completelyestablished. Upon such completion of the connection of auseleetedanswering-jack circuit and a calling line, the calling indicators 59-60are operated in a manner to be spe'ci- 'f' fied, whereupon the operatorconnects the answering-plug 58 of an idle cord circuit with theanswering-jack connected with the calling line. This answering-jack maybe of the form commonly in use or it may be 'i of the form illustratedin Fig. 6. I do not, therefore, wish to be limited to the constructionof the answering-jacks or the construction of the plugs designed forassociation with the jacks, nor to a plug that is adapted for insertionwithin the jacks as contra-distinguished from jacks that are adapted tobe received by the plugs as indicated in Fig.

A6. I use the term jack, therefore, in the broad sense of a'switchelement adapted for association with cord circuits, and have used theterm plug in the broad sense of any manually operated switch partbelonging to a Cord circuit adapted for engagement with the contacts ofthe jack. When the plugs are out of engagement with the jacks and ananswering-jack has automatically been connected with a calling line,- apart `of the circuit through the calling signal' 59 is made up of thepivoted contact 59I-.engaging the contact `592, the contact 59 beingthen removed from the grounded con- When the operator engages theanswering-plug with the selected answeringjack, circuit through theline-signaling apparatus is broken at 592, but the contact 59 engagesthe grounded Contact 59 through the contacts 59 and 59" together andthereby separates the contacts 59' and 592. The ground 593 is placedupon the conductor 56 before it is ,removedl at. 592, so that circuitthrough the magnet 11 will/still remain intact for the purposes thathave been specified. After the o )erator'has engaged the answeringplugwith an answering-jack, she ascertains jas cuit Ato be 4ve theconnection desired, inserts the connecting;` plug companion to theanswering-plug into the jacl"-of the called for subscriber, andsignalsfftliecalled "for subscriber "with any suitable apparatus; suchas that inch'- cated and which is, so well lunderstood.by those skilledin the art as to need-n o including the supervisoryapparatusftl `.t:Ihave shown is so well understood by ose skilled inj the art that adescription thereof would be superfluous. 'lliecirci'iits incliiding and'controlling calling signals 59-"60 will be'lapparent and need` n'otfbedescribed.

Iftheca'lling subscriber had restored his telephone before the operatorinserted the answering-plug, circuit through magnet 58 would have beenopened at the calling subscriber's switch-hook` so `thatcirmitthroughthe magnet 11 would hare beenopened at the released armature ofmagnetS.' After the operator, however, vhas inserted the answering-plug,the control ofthe; magnet 11 is hadl by he' at 59-593. t The' operatorwhen breaking connection between calling and called subscribers,withdrawsthe plugs of the cord circuit to open'f'circuitI through'magnet 11 at l59' 'and 5933, tliearmat'ure of magnetS beingr thenunattracted because of the opening;r m the clrcuitot said magnet o coonthe deconnection withj 'a Y toothl 26. his th answerlngiendotttheansaemn g" Sub 1b in ndcs'fsiinlar-armatureiswi 10 SS theanaivering.te-Iim'i'nalfcontA df@- script-ion.` Theentireicord circuit'apparatus A in the left of th( drawing. The magnet 71 operates the arm:ture-switches 9 1() for the same purpose that the magnet 11 operates itsalimilture-swit:hes 9-.-10. The magnet 24 is included ina c'1cuit1-thatcontains the bat- 72 when rnor motor upon the rrangement to that f thedrawing, like both governor mocharacters of referparatus and circuits:heirlght (if-Fig'. 1 that have y Qirangeiiients corresponding )arteuponfthe left of the ligure,

y are also glien, similarcharacters of reference.l though in solne casesthe mechanical association may not be absolutely identical. Aftercircuit through the conductor has beenclscd upor thfeselcction of anidle an swering-`jack cil cuit switch by the calling subscriber (nowspeaking of the apparatus upon theright) thejmagnetf is operated toattract armature and complete circuit throughvthe magnet 'Q15 which maybe 4traced fr@ 1i tlie1-,gro11n led batteryA through the d contact.-After each attracjiirelfl, circuit through the yut'he separation of thewhercbY tl a li'ature'Q is released and is thereuponremofed toa reverseposition by the spring 28, w lich spring at the same time causestherestoratione'f the lazy arm toits initial positi' whereupon circuitthrough the magnet i inst closed, which operation' is vcon lnutd untilthe answering-jack circuit `n iotor lafs operated the answering ends ofthe idle .a'lisyeringjack circuit, to bring'- tjhexsaiifie intojconnection with a L'ca-lling subscribers `1lineY terminal contacts..lVhen thisfresuf t is achieved,V the arm 13 is grounded by way of. thearnniture-switch Vl() of ,the calling s Ibscriber,. whereby the mag'-net 71-isrin`cluo ed in a. circuit that may be traced Yfrom 'he groundedbattery 23 throughthe ma guet 24, the armature 35, its

'contactgrpthegmag net 7l', the switch-arm 13, to .thegroundedarmature-switch 40, whereby `the arif f magnet i4@ whe reby'the'magnet71 is ener,

ture '25 remains attracted by.. the

gized. Tiee'norgization of the magnet 7-1 l mental circuit for the amature 7l of magnet t 71, the armature i lictorv 5G that has a' groun065 es't'fb ish `'Yt'h'ereupon 'After a. calling` li1 ie l 1 aSelectedjan idle/"answeringvTits I grounded conta ct, "l

rfi

.l energized until' the cord again becomes idle.

Another result of the energization of the magnet 71 is apparent in thedenergization of the magnet 34, whereby thegovernor motor may berestoredWithout the danger of lbeing re-stepped at the end of a connection.

Theprovision of the circuit afforded by the armature contact 75 and theground 56 upon conductor 56 is for the purpose of maintaining circuitthrough the winding ol magnets 71j and 24, which otherwise would bebroken upon the disconnection of groundfrom the armature-switch upontheoperation of the armature-.switches 9-10 which cause in the mannerheretofore set forth, the operation of the cut-off relay and theconsequent removal of the armature-suitch 40 from ground.

Should there be two or more subscribers in any group calling at thesaine time, it is gp parent that the answering-jack circuit tiarelingswitch of the first idle answering-jack would select and make connectionwith the first of the calling lines which the arms 7 8 and 13encountered and that the switch 29, being then released, wouldimmediately select the neXt idle answering-jack circuit, owing to theground still present on conductor 41, this operation continuinguntil allof the calling subscribers in a group have been answered.v

A feature of-my invention'resides in. the provision of the supplementalSets of contacts 1212 in addition to the talking terminals of eachtelephone line in` conjunction with the switch-arms 13-13 coperatingwith said contaiixts, all operating in conjunction 'with theanswering-jack circuits.

A. very use-inl ieaturc of my invention is the proiisioii ci" .localcircuits including subscriberoperated switches, as 40, desirably locatedat the exchange and adapted to include a switch-arm, as 13, in circuitwhen placed in engagement with one of the said supplemental line,contacts, 12, vand apparatus included' by said arms in any local circuitthus established, 'which apparatus Will 'serve' to 'effect therestoration of the answer- .ing-jack selecting mechanism, so that saidmechanism may be used in perfecting other connections;

/In the precise embodiment of the invenv' tion illustratedthei'e are, ashas been stated,

i' se as manysupplemental line contacts l2 and as many supplemental linecontacts as there-aire telephone lines. in a particulfn group. There areasmany'sets of ,these con-- tact's12 -'-12 and arms v'1-3--13 as thereare an'siy'eisingzjacks assigned torsuoh` group. In

the embodimentof'the inyention illustrated, there are thus maiy moresubscriber operfor the local cirf'.

ated switches 4:0 provided spends in function torelay 58. 83-84correspond in function-to the .lampsl 559-60. The contacts A85--86cooperate with j connected j in -the cuits than there are sets ofcontact buttons 12 12 and arms 13--13, but the said arms and contactbuttons are adapted to be in eluded. in local circuit with switches 40of calling lines. I do not wish tol be limited, however, to the precisearrangement illus-v trated. l

The system illustrated in Fig. 2 is similar in general respects to thatindicated' in Fig. 1: The system illustrated in Fig. 2 has as a.modification of the system shown in Fig. 1- additional sets ofsubscribers contacts 76-*76 equali'ng in number the contacts 5-5, 646',etc., the provision of switch-arms` 77-77 for sets of added contacts76-76" and circuit conductors 7 8--79, in which conductor 78 there isincluded an auxiliary armature-switch 8() and relay 8l and in whichconductor 79 there is included the cut-olf relay 2, the conductor 79being extended to the multipled spring-jacks, the particular systemshown being a multiple switch-'board system, wherebythe cut-olf relaymay be operated'froin any section of the board as Well as upon theconnection of the answering en`d of an answering-jack circuit with acallingl line. In the system shown in Fig. 1 a side of the talkingcircuit is, employed in the operation of the relay .2, whereas in thesystem illustrated in Fig. 2 the-"conduc-- tor that establishes thecircuit for the relay 2 is not a section of the talking circuit,

illustrated in Fig. 1, ai'egiven similar ref erence characters. Ingeneral, the functions performed by the added conductor are similar tothe functionsperformed by one of the talking conductors shown in thesystem of Fig. 1. The relay 81 corresponds in flinction to the relay 57.The relay82 corre# The lamps'- each otherin opening and closing thecirvcuit -of the magnet 82. The circuit ofV the magnet 82 is iireferablytraced from the grounded battery 23 through the winding '82, thecontacts SCi-85, the sleeve strand of' the answering-'jack circuit,throughthe subscribei"s line, back to the tip strand o-f said circuit,to the tip line spring andthegrojind.

87 engaging said line-spring when the plug 58 `is withdrawn, soithatthecircuit con-- taining said magnet 87, -Whereby sa id 82 is not onlyopened4 at 85--86,'but is also opened at the groundl magnet B2 isenti-rely dis= system shown` in'iFig. rather than beingV connected Withone iside` the line terminal, as is the cese of'magnet \of the systemshown in Fig. 1. Upon the inser ion of the answering-plug 5S within anans tering-jack, a circuit that is maintained during the presence ofsuch plugin said jack, is established for the magnet 11 and Whichjmay betraced from the grounded battery `through the helix of said magnet, thearmature switch 37, the conductor 5G, :to the ground 88 thrown intoconnection with the contiguous and pivoted contact terminal of saidconductoi-.SG by the answering-plug and elements of "the answeringjackoperated thereby; this circuit being establislied for the same purposeas that for which circuit was established through magnet 11 of thesystem shown in Fig. 1 atml, the grounds-88 and 5,93 having-similarfunctions.' In order that the calling 'signal 83 may positively bedisconnected from the line, an auxiliarycircuit opening. and closingswitch 89 is provided. 4In each of the systems of Figs. 1 and2 a relay85) is included in-circuit with the signnls?) and 83, respectively, foroperating the auxiliary calling lamps 60 and 84, respectively, whosecircuits wi-ll readily be understood by an inspection of the diagrams.iThe cord circuit apparatus illustrated in Fig. 2 including theYanswering-plug 58 and connecting plug 61 corresponding to similar plugsof the system of Fig. 1', is well understood by those skilled in .theart and a description of the instru' mentalities comprising the samewould be superfinous.v I have indicated in Figs. 1 and-` 2" hose systemsthat are most commonly employed,.throughout the United States in' largeexchanges, the two beingr illustrated in order that `the wideapplicability of my inven't'ioninay be readily understood. I do notdeem'itessential to illustrate further systems and the application of myinvention thereto; U In-thiejsystem illustrated in Figs. 3 and th'sainefrgeneral systemsY havebeenillus# tra-tedfthnt are shown in Figs.'1 and 2 re-' spectively.

' It W'll have been observed thatthe .mainfunction '-.ofi `the switchQ29 and the elements' in` coipera'tive relation therewith has been 50,performed as soon as an-answering-jack circuit'rnotor corresponding toan idle 'answering-jack circuit has been set into operation. thesaid-switch 29 being restored to its initial. condition `as soon as theselected answeringjack` circuitl `motor has brought Ythe answering endof .thejansWeIi'ing-jack associated therewitl into connection with thecontacts of a call; ine, `soth'at another subscriber i iSwitchininitiating another ndicated one sucht switch 2S) eft ofA thedraw-ing and another lit i thedrawing for: the purss battiti-,isunderstood4 that 1only'on`e such Vorgan-ization m. 1

In the system illustrated in Figs. 3- and 4 the subscribe "s governormotor is restored once in a condition to ,be used by another' callingsubsc'iber, this arrangement being preferred to 1hat illustrated inFigs. l and 2 in which tile governor motor is thrown out of servic(until the answering-jack circuit motor selected by it has finished itsoperation in connecting the answering cud of the selected answering-jackcircuitwith the line terminal contacts of a callingsubscriher. In thearrangement'illustrated in Figs. fland 4 the answer ing terminalcontacts of the answering-jack circuits have initial pt sitions to whichthe," are restored whentlicir answering-jack circuits are disconnectedand placed ou* of service, this arrangement differing from thatillustrated 'in Figs. l and 2, Where the traveling answering ends oi"thc answering-jack circuits remain in the positions Where they were lastused. By this arrangement it is apparent thatseveral answering-jack.ircuit motors corirsponding to a group of t1 flephone lines mayhdsucccssively started before the controlling ground at the switch t!)is removed. It will be apparent that by this apparatus the governormotor common to a plurality of lines -niay be operated in v( ry quicksuccession as' it is released after s1 arting anI,answering-jack circuit motor without having to be maintained in the positior to which ithas-heen actuated by acalling s'ibscriber until the answering-V jackcircuitmi tor has effected connection he- 'tween a calliig sl'ibscriberand an idle ansWering-Jack circuit. Several answeringjack circuit nlotors may thus be operating at the same time, therst selected idle an-`swering-jack circuits hav-ing connection eifected with calling lines.That is` the idle answering-jack circuits are connected with callingtelephone lines inthe order in which thcyhave been selected by the'subscribeWs governor motor-,those started by the governor motor inexcess of the number calling, which are the last to be started.returning to their normal positions.. Bv thislarrangement theansiferingends of the answeringjack circuits ii sweeping over the lineterminal contacts of a' number of calling subscribers. stop ftthenearest calling'line terminal contacts independently of theanswering-jack, circuit .startedby calling subscribers. '.hat is, Vofa`number of calling subscribers in;` i groupv oftelephone lines. one

subscriber may 4causeonei'answering-jack cirl cuit motor to start,ywhich answering-jack circuit motor may eifectconnection of anotherlower nu nibered calling subscriber with an idle Ia-nswe'ing-jackcircuit Referring niw more 'particularly to Fig. 3, .reach sl-ibscribersstation, A--B, is prov-ided with the customary common batterysubscribers apparatus, a switch-hoch at each station serving operativelymetallically to unite the sides of the line when the receiveris-re'moved. I do not deem a detailed description of the subscribersstation apparatus'to be essential, as the illustration is suflicient tomake the same understood by those skilled in the art, and otherarrangements ,may be employed at the jsub-station. As in the fcase ofthe systen'is shown in Figs. lf'and 2, the system indicated need not belimited to common battery practice. Each si'tbscribers line indicated isa lnctallic'line and extends in two branches to the exclmnge where itterniinates in contact-s 1--1 of a cut-ofi1 relay 22. These contacts arenormally engaged by the armatures oi said cuto'' relay and arepreferably pivoted contacts and are swung upon their pivots by saidarmatures when unattraeted, to discontinue, the. telephone line at thecontacts 1-1 The upper armature 13 of the relay constitutes avterminalthereof and grounded. The lower arn'iature l4 constitutes a terminal otthe, magnet 38. rThe system illus-,1 trated being-a multipleswitch-board tem, the contacts 12 constitute terminals of the ofticeendof the line, which end is supplied with the line-jacks 3and there arealso i provided uponother ysectionsof the board than where jack 3 islocated,othc r jacks .4 in connection with the 'saidcontacts ift-12.Multiple terminals 5 andmultiple terminals 6 6 are Connected with-theterm'fi-l'ials 12-12* and `constitute the telephone Y line terminalcontacts, as will be understood.

The' contact buttons or terminals 5 6 are arranged in circular rows overwl'nch sweep the -answering-terminals 7--8 and 7-8,-

which answering terminals are normally connected with the answering-jackassociated therewith, but which connection is pref'- erably broken atthe armature-switches 9 1() in -thecou'rse .of the selection of ananswering-)ack-circuit, so that the apparatus illus- A trat'ed' may beeffective for the purpose of 'the "invention, the said armature-switches9%.'-10 being included in the tip and sleeve sides'of theanswering-jack' circuit, respec- Y tively, and being serially included'in cir- .With the switch-arms 7 8 and the conn" ction/.with saidswitch-arms. There are alsoprovided the additional rows of contactbuttons12 '12 whose general'purpose is s'rnilar to the ,purpose of thecorrespond- Varg1-ry:

designated contacts of Fig. 1, but whose circuit relations are somewhatmodi`v fedjin View of thealtered character of the system of Fig. 3.v Thecontact or. switch.-

a'rms 13,-13". sweep vover` Contact =buttons 12%12?, these contact. armsbeing provided forthersame general purpose for which the correspondinglydesignated contact arms, of

1?--12'when said contacts are in con- Fig. 1 are provided. 'lhesearmsare pivoted at the centers of their circular rows oi contacts and arepreferably flared or enlarged at their free ends, so that they will masame time, so that one button willnot be freed from connection with acorres].)ondng arm until, after the succeeding button has been engagedthereby. In the system shown in Fig. 3 it may be understood, forexample, that thirty answering-jack'.circuits have been assigned to agroup of live hundred lines, that the contact buttons number fivehundred, one connected with each line, that the number of contactbuttons G equals five hundred, one connected with each line, `and thatthe number of contact buttons 12 equals live hundred, one for each line.The contact brushes 7, 8 and 13 constitute a set and there are as manysets of Contact brushes as there are answering-jack circuits assigned toa group of telephone lines. Said contactarms of each set are desirablyoperated by a common prime mover 15; that is, there one prime mov-erprovided for each ot said sets, which prime mover may include the shaft14E upon which said brushes orarms 7, and 13 are mounted, the springmotor 16, the wheel 17 upon shaft'l, the said wheel carrying teeth 1819, arranged in peripheral rows, across which teeth the polarizedarmature 20 of the motor is adapted to oscil- -late by the agency of thefield-windings .21'

and vthe source of alternatingcurrent 22 when said source of current is"included in' a closed circuit with said windings, this prime mover beingsimilar inits operation to the prime mover illustrated upon the lefthand of Fig. 1..

VVhe-n a subscriber initiates a call, the answering end of an idleanswering-Jack circuit, 1n thls case 'the first, 1s automaticallyconnected with a. set of .terminal contacts,

i this automatic connection being occasioned by the operation of thesaid answering-jack circults motor.' In order that the subscribersgovernor motor nia-y immediately 'be used after causingan answering-jackcir- I cuit motor to start, so'that another answering-jack circuitmotor'maybe'4 soon started by another calling subscriber withoutwaitingfor the rst 'answering-jack circuit inotor to complete its operation inselectingan (e contact with adjacent buttons at. the

idle answering-jack circuit, the arrangement.

illustrated .isl preferably employed'. "TT-he ..120 governonmotor shownupon the letti-and that' shown opona-the rightech includes a switch 29operated' .by the armature of an electro-f i magnet 30, as will be.hereinafter more articularly set "forth, which switch 249 rides ,overa. series of' contact buttons 31 constitutingterminals of' conductorsextendi'ngto .the

various answering-jack 'circuits of a group,

there being as many contacts 31 las there are answering-jacks ofsaparticular lot assigned to a group of lines, ple chosen thirty suchcontact buttons. A complete conductor 32 is shown extending from.. oneof the contact buttons 31 to the answering-jack circuit that is shownuniting the Subscribers stations A-B. Normally, that is; when itsanswering-jack circuit is idle, this conductor 32' is connected with thegrounded battery 23 by way of the switcharm 13 whose normal position is-upon they -this larmature-switch being attracted to effectconnectionwith said ground because a circuit is established by saidsubscriber through the magnet 38 operatings\\'itch 3f) when he removeshisI telephone. for the purpose of making a call,` which'circuit may betraced from the grounded battery 23, through the winding of magnet 38',the armature l, over the subscribers telephone l-ine to 'the contact 12,tothe grounded armature-switph 13. The subscribers goyerno'r inotorincludi ing the switch 29, the operating magnet 30 g l5 servingtoeattlact 1 gagcthc hook t8 'w1 Vder that the sprm;`

and associated parts, is similar to the subscrlbers governor motordescribed particu- .larl in connection withFio'. l and a re ieti tion ofthis description will not, therefore, be required. A callingl subscriberin initiating a call. effects the travel of the switcharni 2f) over thecontact buttons 31 until a contact button that is connected wit-h a con#ductor $52 that is associated with an idle'ans\\'ering-jacl{ circuit isencountered, whereupon the motor corresponding to said ans\\"eringjaclcircuit is set into operation, 'as

A will he hereinafter set forth. As soon as the answering-jack circuitmotor is set into op eration; that 1s, as soon as a vcontauict 31 corres)ondin'f to an idle answcrjnffack circuit b n .l

(inthe case ofthis system the first idle ansuernJg-jack circuit becomingassociated with the switch-arm 29) is engaged by the s\\itcl;1-arm orswitch 2!) said armis immediately reciprmaited to its initial positionbecause the said switch-arm is pe1flli;l|it .|ltly grounded through the;winding oa magnet l5. circuit through said magnet 4being thereforecompleted whena conductor 252,`grouud l ed, aszzhas been specified.at the. battery 2., 1H

connected with the elelnel 4t2!)l tl in"witlulra'wiugthe(v ment 4withthe ser there being in the exam- -result is accon circuit Vmay. be tfaced vfr switch 29, the circuit established through the magnet by theswitch 29 must be open, yso that the sail spring will not becounteracted by the at :raction of said magnet. This plis-hed bythe'niovement of the switch-urn.. as 13.. operated by the correspondingai swering-jack circuit motor from the cont: ct `of the conductor 32'normadly/engaged bysaid switch-arm, therebydisconnecting the battery 23from said 75 cond ctor tu `open the circuit including thehiugn-et 45',whereafter the spring 49 may lift the dftent 46 by pulling the'eatchwhereupon the switch 29 may be resturedby t he spring +7. after ananswringv-jack circuit 'motor'has been started to operate by a governormotor operated by a calling subscriber. the said governor motor isreleased, permitting it to act without de ay in-starting another an- $5swering-jack ci lcuit motor in case another subscriber of the group towhich the governor motor has leen assigned initiates a call. Asupplementa contact is provided so that the switch arm 2!) may berestored in 9c case all the conductors 32 are associated with busyanswering-jacks or the switch-arm29 has otherwise tlareled its fullcourse without having stalted an ans\\eringjack circuit Inotor. Thecontact button 5() is con- 95 nected by way of the switch 51 with thegrounded Ybattez-y so that. when the switch 29 engages said button50;..circuit throughthe mag net 45' willl be completedto draw up the arnature 44 and effect engage 10g' lnent of the catcrlS with the detent 46,immediately when -after circuit through `the magnet 45, is opi-.ned at51 so that said magnet 45 is deinergized aud spring 49 is free to liftthe detenl 4.6 by the elevationvof the 1.95 catch 48, whereupon thespring/17 reciprocally4 moves` the switch 29. The switch-arm 13 operatedb'y t ie selected motor, together with the companion `switch-arms 7 -'8,sweep about' their assoc tacts until the co ltacts corresponding to thecalling.,r line are thereby engaged. Prior to the connection ol thetalking terminal Icontacts 7-8 at the answering end of ananswerinY-'aclc circuit with a callin" sub- 115 h l y r scribers line.the armatare-switcliesll() are attracted bythe magnet -11 through whichcircuit is at ont-e establi 'l h [m 't battery QSItIn-oug rthewr ndilsrmag 12u net 1 1', to the tl en unattracted armatureswitch il() ofmagnetl. to the contact button in'eugagement w th the selected conductor32, to the ground it the magnet 45... Inthe system `illustrated in Fig.3each ofthe con- 125 t (its. s normal ly' groundedslat tv .f

Thus, directly gc i `ated circular rows of conr11o which occurs when asubscriber first initiates a call, the? ground at 92 being restored as'soon aS the cut-off rrelay/l2 is ei'iergized` There is thus only'abriet interval in which venting the magnet 11 from becoming enerstoredgized when the ground 92 has been re- The energization of magnet 91. iseffected by the closure otytlie circuit that may be traced from thegrounded batteri7 23,

through the winding of said magnet 91, the sleeve side of theanswering-jack circuit, the armature-switch 10,*thc arm S, the windingof the cut-ofi` relay 22, to the ground of said cut-off relay. Upon suchenergization, the arinature-switch 90 is operated to open the circuitcontaining the magnet 11. When the magnet 11 is energized, itsarmature-A switclr is grounded to set the selected answering-jackcircuit motor .in operation. Such. energ-ization, as has 'been stated,is efected'iininediately upon the engagement ofthe switch 29 with a.button 31 that is in connection with a switch, such as 13, in cirH cuitwith an armatureswitch 90 that is unattracted because of theassoci-ation of its operating magnet 91 with an idleansweringjack-circuit. In. this way the selected an sweri'ngljackcircuit motorjs started to operate at once when the subsribei"s governormotor has performed its function. said governor motor thereupon beingrreleased as has been specified. lVhen 'the inagnetll has its'circuit`ope1ied. the priiiie mover or an i swering-jack eircuitinotor15 is thrown out of service, as the circuit of the windings 20 isthereupon opened at This opening of the circuit-occurs and ismaintained, as hasbeen stated, lby the attractionof thearn'iature-switch '90 which is occasioned Lipoiithe coiinection'of thegrounded cut-oli' relay- 2 with the magnet 5l,.wliich latter result isnot occasioned until the calling siibscribers line is connected .with ananswering jack circuit.

groiindcdciit-otf relay with the winding` of magnet 91. cannot occuruntil thc switch l() has beenA released bythe magnet 11'. This releaseyis effected whentlie armatarc-switch 90 included in circuit'withthe'inagnet 11 has its associate arm4 1.3 come into contact: withthe'but-ton 12 of a calling-line from whihthe ground at 92 is at thisparticular Obiiously, such connection of the instant removed, thecircuit through the winding 11 being thereby opened at 92. This ground92, as hitherto stated, is restored to the contact 12 engaged by thearin 13 when the c.ut-off relay is included in circuit, but the magnet91 has in the meantime operated the switch 90 to open the circuitincluding the winding 1l,. so that the switches 9-0 are permitted now'to remain in their unattracted position during connection, while at thesaine time the motor wind ings 21 are caused t0 remain passive becausetheir circuit is opened at 35, whereby the aiiswering-terininals oftheausii'ering-jack remain in engagement with the selectediline contactsof a calling subscriber. The call? ingr signal relay 93 is now broughtinto circuit that is completed byl way of the subscribers switch-hookand which`circuit incliides the grounded battery 23, as will beapparent.l saidv relay thereupon being energized to attract its armatureand close. auf other circuit containing the calling lamp 94 and therelay 94 governingr the circuit including the auxiliar) or pilot signallai'np SH2. The operator in response, to this signal, inserts theanswering-plug 58 into .the se; lected ansv.'eiing-jach alid therebyopens at 95 the circuit containing the elements SMWQLL. The operator in.response ,to the signal at 94, ascertains the connection desired andeffects connection with the called subscriber in a manner wellunderstood and which need not be described, nor need the cord circuitapparatus, with the aid of which she is able to perform -her Work, bede' scribed, as the apparatus illustrated and lts functions are wellunderstood by those' skilleiliii the art. Prior to the insertion of theanswering-plug, the,A calling subscriber may effect a restoration of themotive apparatus associated with the answering ends of theaiis\\'eiiiig-jacl that have been moved into connection with bis line,as `will be understood Aby the descriiition shortly to be given. `Afterthe answering plug has been inserted, howerer, the restoration of theappara-tus is within the control of the operator. In orde-r to effectthe. restoration ..0 the traveling ends of the answering-jack circuits,the switches 7,"8 and13 continue in their previoiis, .direction ot'rotation, 'but the polarized armature 20 for this purpose must again be'set into motion, to which 'end ther .magnet 1,1 .must now be. energizedto ground I his result 'is accompllshed the switch 35. by the operatoron withdrawing the answering-plug 58" by closure of the contacts 95,'the contacts 9G being closed because of the denergization of the magnet93 occurring iipon, the restoration of the receiver upon the switch-hookat the calling subscribefs station. never been inserted, suchenergization of the magnet 11', would be occasioned at the con-Correspondingly, if the plug 58 had y tacts 9G, the contacts 05 beine;then closed, the calling subscriber. ot course, having restored histelephone upon its switclrhook. (,ircuit thus established at S15-0o maybe 5 traced from the grounded battery 28, to the switch ',r the contactsSla-M6, the magnet 95. the arinature-switeh 00, to the ground at U2 nowpresent. The armature of magnet 05 is thereupon ittracted. whereupon the2o grounded catch lllz'engaees the armature oi said magnet 95. whereb)vcircuit through magnet 11 is established for the purpose specified.which circuit may be traced .from the grounded catch 102i the armatureof magnet 05', the windingotniagnetll, to the grounded battery 23,whereupon the wind ings 21 othe alternatin currentinotor are set intooperationcircuitthrough winding 11 being inaintainedfmeeliaiiicallit at102'7as the arm 13 in being restolf'ed might enconnter theig'ribunjdless contact Uien the initial po'siti-onsl "e been reached,the pin 103 strikes-an `il lated!finger projecting from the pivotedcontact or catch 102, there- 25 by witlnlrawing the said catch fromengagement with the arlnatureof magnet 05 to open the circuit ot magnet11 and thereby cause a cessation ofthe polarized armature. Q0. so that.the switch partsT` 8 and 13 reinitial or no rlnal positions.

i gpfo'nf lthe .lower right similar in .elecine! respects isnst'ru'c'tion from l lhe'ilallns 7. I82 4and 132 correspond in functionheal-ins 7, 8 and 13, lult the, former 'a-l y.are designed forrectilineal travel, to which end certain `modifi- 43 cation is requiredin the prime lnover or answering-jack ,circuit Vmotor that effects thetravel of si `d"a`rrns,it`or they n lust be adapted vfor reciprocationinstead ot' travel in a continuous direction to effect their .pui-pose.

4a .lhe contatlt 72, 2 and 132 are similar in. function to the contactsprovided in association with the arms 7, S-and 13. respectively. Thereis,

however, a 5G 106 forciilf with th( `answeri'ngjack circuit equipped'li-1s should tra velt-heir fullest ex- ,ting the Aconnection of acallingfliue, said arm 82 i he restoration `of Y ,A s ini-lar, to that'the left and similar parts are upon t sh own a. ngagetLb-a'switchtftli-lfmlglihtlle magnet 107 is ircuit may be traccdflgom the `battery 23, through the. winding i' thcialrlnatnre,switch108,the

Vcuit through the winding llpiis o 'n d `operate the arinat llre-switch11'5- v -niay be restored by the spring 122 n1 edfupon the left ofVbuttons associated with the arms additionallnlt `ground contact ma 72,8? andl, so that in case '523, toithe magnet 101', the parts -1-1- 1i tothe ground upon part 117;@Thc .spring l 122 4restores the ausw eringjackcircuit motor haracters of reference. When' switcharn1 132, thaconductor 32, theswitcharin 29, to the grnund at magnet' 45" withresults'that will V)e understood 'in 'y1 w of the description of theleft hand subscribers governor motor. The arlnatureswtchl 109 70 isthereby operated to close circuit ythrough the winding 110 of the motoroperating Athe switch-arms 7 2 8L and 132 in a manner that is obviouswhen thi wayin which theswitch'-V u arm is operatel is understood fromthe 75 description previously given, and I Vwill not, therefore.describe the` motor operating. ineclwnism except to describe certa-incircuit l changes that occuito change itsoperativccondition. When inanswringfjck circuit has been connecte( with a callinggline, cir- 109similarly to tl le opening offth throughthc windings 20`at`35'; lionetailed description of theI oplei-litio magnet 107 will n'ct be given?-vl'lhye jo tor 111 that includ s the magnet same circuit relations,confie changes in connecnions thatt'h 113 has; therefore, when thescriber has been co nnectc-d with iug-jack circuit, thi` magnet 112 u toclose circuit through theinaig,i

connection of the catch 1,16 with 117` so that the sp ringv118 'may saidcatch .and feifent'the withd detent 117, rso "that the V arms 'i'2through the in agnel 11-1 may be traced-from the ground thrownrupon theurinatllre 119 upon the' energizition 4of magneti 112, through thewinding.,lr of said ina'gxietolll, over a conductor 12) in associationw'itlitlie answering-jack circuit selected correspondingto conductorlill, the upper-armatureswitch of magnet 12, to the grounded"battely 23.Vhle the magnet 111 is energized only when the switc hes 72, 82 and-13lare to, be restored, the mag net 112-is energri "d gifm'- V110n'lediately upon the connection of'a calling line with an answeririg-jack circuit, whereby the circuit including the magnet 10ft'^ Visopened, at 10Sto maintain lnagnet'lOTfde energized until disconnection.The engage-` ment of the. parts-116 and 117,4 (occurring los , upondisconnection as above described,)= part 117 being'gounded, circuitthrough inagfnet 107, willie may4 ,be traced fron, the,` groundedeifccts'the closure` of il, t v ,l

switch-arms when th dog 117is withdrawn. Although such circu t isestablished-it will now have no control if the winding 110,'cir# 'i jcuit throufrh which winding' .isopec'd at g 115. but tl, switches 9-10will be' moved to disconnect the. connecting end of thelanswering-jackcircuit from the callinglin'e 139 ,izo 4

